Low cost 10GHz Transverter
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John Quarmby
For those of you seriously interested in getting going on 10GHz Rainscatter or EME, Matej OK1TEH has informed me that there is stock available of a low cost transverter made by OK1FPC along the lines of the DB6NT Mk2 10GHz transverter, it needs an external LO source at 106.5MHz, such as a Leo Bodnar GPSDO.
Details are here: https://ok2kkw.com/next/ok1fpc_10g.pdf 73 John G3XDY |
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Conrad, PA5Y
I keep banging on about this but is the Leo Bodnar unit with its accompanying spurs suitable for use as an LO directly. Am I the only person who has checked this? I use several LB mini GPSDO but usually to lock a Xtal LO. They are pretty ugly to use as an LO directly. I did not check 106.5MHz but I did check at 101 and 116MHz. Maybe on 10GHz it does not matter, maybe the spurs multiply up sufficiently to end up OOB and easily taken care of by the transverter filtering. Some are quite close in.
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Can anybody check? 73 Conrad PA5Y -----Original Message-----
From: UKMicrowaves@groups.io <UKMicrowaves@groups.io> On Behalf Of John Quarmby via groups.io Sent: 23 November 2022 13:39 To: UKMicrowaves@groups.io Subject: [UKMicrowaves] Low cost 10GHz Transverter For those of you seriously interested in getting going on 10GHz Rainscatter or EME, Matej OK1TEH has informed me that there is stock available of a low cost transverter made by OK1FPC along the lines of the DB6NT Mk2 10GHz transverter, it needs an external LO source at 106.5MHz, such as a Leo Bodnar GPSDO. Details are here: https://ok2kkw.com/next/ok1fpc_10g.pdf 73 John G3XDY |
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Dominique Dehays
Hi,
U are rigth, but nowadays nobody cares abt spurs and phase noise because synths and poor gpsdo are much simpler. Personnaly I don't use these simple solutions in my rigs 73 Dom |
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I use one for the Bell Hill microwave beacons on 2.3 to 24GHz delivering 10MHz. All but the 2.3GHz beacons there use reverse-DDS locking, so wideband spurii won't pass through. GB3SCS on 2.3GHz uses an SV6AFM AD4351 module generating directly, driven from the LB at 10MHz. When I checked the PN of this it was considered acceptable for a beacon on a high remote spot. I was a bit sceptical when the idea was proposed (the change to an LB reference was quite recent, after the old simple-GPSDO failed) but knowing the RDDS would clean up all the higher frequency beacons, wasn't too concerned. SO far, the new SCS has received favourable reports from a couple of stations who complained about the spurii on teh old one (and that WAS bad) I will fire up my LB, use it to drive an AD4351 and have a check Watch this space Andy On Wed, 23 Nov 2022 at 13:01, Conrad, PA5Y <g0ruz@...> wrote: I keep banging on about this but is the Leo Bodnar unit with its accompanying spurs suitable for use as an LO directly. Am I the only person who has checked this? I use several LB mini GPSDO but usually to lock a Xtal LO. They are pretty ugly to use as an LO directly. I did not check 106.5MHz but I did check at 101 and 116MHz. Maybe on 10GHz it does not matter, maybe the spurs multiply up sufficiently to end up OOB and easily taken care of by the transverter filtering. Some are quite close in. |
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Hi Conrad
Just made a spurious plot on a DB6NT 10G2 XVTR using a LB Mini GPSDO @106,5 MHz and a HP Signal Generator @144,2 MHz. Also measured phase noise -89 dBc/10kHz.
See attached file.
Vy 73 de OZ1FF/Kjeld
+45 4021 1119
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Dominique Dehays
Hi Kjeld , no inband spurs? Close to the carrier? 73 Dom Le 23/11/2022 à 17:16, Kjeld, OZ1FF a
écrit :
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Dominique Dehays
me agn , if I look at the datasheet from Leo Bodnar , I read: Get +11 dBm at 125 MHz with clean spectrum. this should give a big 300Khz spur but maybe it is not the same at 106.5? I don't know what " very clean" means a -100dbc carrier at 106.5 needs a good measurement procedure to be measured but will give something 60db stronger at 10Ghz. Pity I don't have this gpsdo at hand , I would be curious to measure this. 73 Dom
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There is an almost infinite :-) choice of register settings to get any particular frequency and which ones are chosen will impact the spurii/phase noise. It's worth looking at the data sheet for the Si5328 and seeing how it works. I wrote some software to choose register settings for my dual output one, but that of necessity has to offer a whole choice of values, presented in a table, and just pick one that may work better or worse than another. AND the values it gives have to be typed manually into the LB diver software as the USB driver code for the module is an unknown. It's all very tedious. Andy On Wed, 23 Nov 2022 at 17:10, Dominique Dehays <f6dro@...> wrote:
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geoffrey pike
There is as always Dieters DF9NP range of LO and you could straight in at 2556 MHz assuming there is a final quadrupler in the transverter. cheers Geoff GI0GDP Actually the old ADF4351 at 106,5 isn't that bad
On Wednesday, 23 November 2022 at 13:01:22 GMT, Conrad, PA5Y <g0ruz@...> wrote:
I keep banging on about this but is the Leo Bodnar unit with its accompanying spurs suitable for use as an LO directly. Am I the only person who has checked this? I use several LB mini GPSDO but usually to lock a Xtal LO. They are pretty ugly to use as an LO directly. I did not check 106.5MHz but I did check at 101 and 116MHz. Maybe on 10GHz it does not matter, maybe the spurs multiply up sufficiently to end up OOB and easily taken care of by the transverter filtering. Some are quite close in. Can anybody check? 73 Conrad PA5Y -----Original Message----- From: UKMicrowaves@groups.io <UKMicrowaves@groups.io> On Behalf Of John Quarmby via groups.io Sent: 23 November 2022 13:39 To: UKMicrowaves@groups.io Subject: [UKMicrowaves] Low cost 10GHz Transverter For those of you seriously interested in getting going on 10GHz Rainscatter or EME, Matej OK1TEH has informed me that there is stock available of a low cost transverter made by OK1FPC along the lines of the DB6NT Mk2 10GHz transverter, it needs an external LO source at 106.5MHz, such as a Leo Bodnar GPSDO. Details are here: https://ok2kkw.com/next/ok1fpc_10g.pdf 73 John G3XDY |
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SAM JEWELL
My solution for 'replacing' the drift prone LOs of the early DB6NT transverters is to remove the existing crystal and arrange for an external LO input at 106.5MHz or whatever that particular transverter requires. This works well with my 9cm transverter, using a Crystal near 135MHz.
I place the removed crystal into an SM5SBZ-modified Butler oscillator, as used in the Anglian and Iceni transverters. The crystals always seem to be easily adjusted onto the correct frequency and with a PSA4-5043 amplifier, over +20dBm is available to play with. This is injected into the new transverter LO input socket at a level around 0dBm. An attenuator is definitely needed. Don't leave out the LO amplifier as it is good buffer. An LB Mini GPS is then injected into the new Crystal oscillator at the required crystal-replacement frequency and at a level between -6 and 0dBm, so another attenuator is needed. Levels as low as -10dBm work well at 106.5MHz. The modified Butler injection locks easily and the output at 106.5MHz (or whatever) is clean of any spurious from the LB and the PN of the new LO may be much better than just using the LB. My tests indicate that the PN should be not much worse than the original crystal multiplied LO. Trying to injection lock the original transverter crystal oscillator is possible, but often fraught, as the injection level can be very critical and easily break up into multiple spurious outputs. This is my solution. It may not be to your liking, but it works well and is relatively easy to implement. 73 de Sam, G4DDK Sent tomorrow from my iPad 10 |
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Dominique Dehays
Hi Sam,
Same here, all bands from 144 to 47 ghz. The external oscillator is my version of the df9ic plvcxo. Same on / p rigs. The original oscillators of the xtal versions of db6nt are not stable enougth, they detune, especially when driving on bad roads to reach mountain tops. 73 Dom |
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Hi Dom
Se attached plot made this morning. Inband there are +/- 600 kHz spurious. 
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